Word Problems Leading to Simultaneous Equations

To solve word problems you need to write two separate equations using the information provided. Then solve the equations simultaneously using one of the algebraic methods. 

Example 3.2.1:

The sum of two numbers is 30 and their difference is 15. Find the two numbers.

Solution 

Let the numbers be x and y 

The sum of two numbers is 30 ⇒ x + y = 30

Their difference is 15 ⇒ x – y = 15

x + y = 30 ………….(1)
x – y = 15 ………….(2)

Add equation (1) to (2)